Tuna can be cooked any way you like, though you will want to keep in mind that commercial tuna is cooked twice to ensure that all bacteria is killed. You will want to keep in mind that when tuna is rack-baked it loses a significant amount of nutrients so you are not able to benefit from it nutritionally as much as you would if you chose to broil it.
If you want to bake your tuna, it will be important to follow certain steps, starting with preheating your oven to 350 degrees Fahrenheit. You will also want to spray down a baking sheet with cooking spray so that it does not stick. The next step in the baking process involves patting down each tuna steak with a paper towel. Ten you will need to rub some olive oil on the surface of the tuna steaks and then sprinkle some salt and pepper for a little bit extra flavor. Make sure that the baking sheet is in the center of the oven before you get started. You will need to keep your tuna steaks in for not more than 15 minutes.
Those who want to broil their tuna will need to follow a separate set of instructions, starting with turning the oven to broil and then spray a light coat of grease on the broiler pan with cooking spray. After you have done that you will need to pat down the fish until it is completely dry, seasoning it with salt, pepper, and whatever else you want to put on it. Allow the fish to broil for anywhere from 4-5 minutes until each one is ready to eat.